Question

1. Although the model of skin pigmentation based on UV exposure and vitamin production is comprehensive, it still presents a problem. This model does not explain why some northern populations, for example the Sami in Scandinavia and Inuit in Northern Canada, are darker in skin colour than the peoples to the south (the map below illustrates the territories of the Sami and Inuit). The lightest populations in the world are not from the farthest north. Based on the information , infer why these two populations would display a light brown pigmentation even though they live in the remote north.

2. Do you think the impact of natural selection on skin colour is as strong today as it was in the past? Explain in close deteails.

Answer 1

1. Skin pigmentation in an individual is a result of genetics and exposure to sun. There is direct co-relation between geographical ultraviolet radiation distribution and distribution of indigenous skin pigmentation.

The area located to equator, receive higher amounts of ultraviolet radiation than that of area far from the tropics and closer to the poles.

People have different skin colour because their melanocytes produce different amount and kinds of melanin. The amount and type of melanin produced is controlled by a number of genes taht operate under incomplete dominance.

2. No, When anatomically modern humans began to migrate away from the equator to the north where they exposed to less intense sunlight. Need for greater use of clothing cause less photodestruction of folate under skin. This evolutionary change increases the survival of light- skinned gene variants.

In recent times, humans have become increasingly mobile as a different conquences like environment change, domestication ,etc. Many people setting up place far from their homeland, means, sjin colour today are not as confined to geographical location.